Q: What's the right intermediate metal to use to connect the copper
wire/rods to the galvanized steel tower legs?
A: The connectors sold for this purpose use stainless steel to separate
Copper and Galvanized Steel.
http://www.dxengineering.com/Parts.asp?ID=915&PLID=103&SecID=51&DeptID=19&PartNo=PPC%2DTK%2D1
Q: And as to the old copper-clad ground rods, is there a way to tell if
they even exist anymore?
A: From the Erico technical paper entitled “A Technical Report on The
Service Life of Ground Rod Electrodes” at:
http://www.erico.com/public/library/fep/strike/LT0540.pdf, "rods coated
with 10 mils of copper can reasonably be expected to perform well in excess
of 40 years in most soil types" so, unless you have unusual soil, you should
be good for another 20+ years.
73,
Mickey N4MB
On Mon, Oct 25, 2010 at 11:01 AM, K0DAN <k0dan@comcast.net> wrote:
> BACKGROUND:
> I'm enhancing my 12-year-old tower ground system. I have three copper-clad
> ground rods adjacent to the tower legs, each ground rod has a short run of
> #4 copper wire to each tower leg (galvanized steel) at the base. This
> existing ground system also connects to a copper plate inside a Nema box
> about 6' from the tower, and to a 130' buried run to another Nema box with
> copper plate near the shack, and ultimately to the single-point-ground bus
> at the shack.
>
> I plan to add more ground rods at the tower base and shack, also create
> more
> of a grid between tower legs & ground rods. Also add more radials beneath
> the tower for use with planned shunt-fed tower. I have two coils of copper
> strap...will use these in lieu of wire (until I run out of strap).
>
> The tower base, bolts, and other hardware are all galvanized. Tower base
> cage & rebar are embedded in approx 12 yd of concrete. Soil here (midwest)
> is about a foot of black dirt atop clay. None of the galvanized is in
> contact with the soil. Can't say what the soil chemistry is, but years ago
> I
> lost a guy anchor (different tower...R.I.P.) to galvanic action, so the
> soil
> is corrosive in some manner. Other than the copper-clad ground rods,
> everything in the soil is copper.
>
> I have had no previous corrosion trouble connecting the copper ground wires
> to the galvanized legs/bolts, but since I'm refurbishing, now would be the
> time to replace/add hardware if appropriate. All the ground rods are
> copper-clad steel...I have no idea what condition the sub-soil rods are in.
>
> QUESTION:
> OK so the question is....what's the right intermediate metal to use to
> connect the copper wire/rods to the galvanized steel tower legs? Brass
> washers? Stainless?
>
> And as to the old copper-clad ground rods, is there a way to tell if they
> even exist anymore? (Yes, I can see them, but are they still 8 foot x
> 1/2"?)
>
> Suggestions?
>
> Tnx es 73
>
> Dan
> K0DAN
>
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--
Mickey Baker
Fort Lauderdale, FL
“Tell me, and I will listen. Show me, and I will understand. Involve me, and
I will learn.” Teton Lakota, American Indian Saying.
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